Geotech Ltd.

- Helicopter-Borne Time Domain Electromagnetic System


The AeroTEM system is a new and innovative approach to geophysical surveying. The original concept of a coincident coil helicopter-borne time domain system was pioneered by Aerodat scientists in the early 1980's under the guidance of Wally Bokyo (founder of Aerodat in 1969, and founder of Aeroquest in 1988). Aeroquest has since refined the system design into a practical and field-worthy exploration tool that is optimized to provide the maximum amount of information on a target conductor. The resulting combination of resolution, conductance discrimination, and geometric information is not possible with any other geophysical platform.

  • Presently achieving depths of exploration twice that of traditional frequency-domain HEM, greater than 500 metres with the new AeroTEM IV system.
  • Next generation systems will approach depth of exploration of fixed-wing AEM.
  • Highly focused EM footprint provides outstanding delineation and characterization of subsurface conductors, superior to that provided by the much more expensive large-loop ground EM methods.
  • System is highly portable. Can be readily dismantled and re-assembled for economical deployment to any geographic location.
  • First helicopter-borne EM platform to provide the well-established benefits of time-domain EM exploration in rugged terrain.
  • System symmetry about the vertical axis makes target responses immune to bird heading, thereby removing the confusing responses seen by other systems while climbing in rugged terrain.
  • Ideal system configuration for flying in a 'low and slow', tight line spacing survey mode for detailing known conductive targets.


AroTEM flew several thousands of line-km to date, more than any other commercially available helicopter-borne time domain EM system, and has contributed to significant discoveries for numerous Aeroquest clients. AeroTEM has become the system of choice for mineral exploration, because of its compact footprint, multiple axis receiver coils, and on-time measurement capability. The system has been used successfully for copper (Cu), gold (Au), nickel-copper-platinum group metals (Ni-Cu-PGMs), poly-metallic sulphide (Cu-Pb-Zn) and kimberlites (Diamonds) exploration programs.


In 2002 Wolfden Resources made a significant discovery at High Lake where a regional AeroTEM survey led to a drill program that intersected Cu-Pb-Zn mineralization in what is now called the West Zone. High Lake is considered to be one of the highest grade undeveloped poly-metallic deposits in Canada and is providing Wolfden Resources with the opportunity to become a mid-tier mining company. The High Lake area had been heavily prospected in the past including a fixed-wing EM survey and over 100 drillholes. Wolfden Resources was named 'Prospector of the Year' for 2003 by the PDAC.

An AeroTEM survey led to the discovery of the Powerline Deposit in 2002, a Ni-Cu-PGM zone explored by FNX Mining Company Inc in the Sudbury Basin as part of an option agreement with Inco Limited. The FNX discovery was made within 75 m of a major power line corridor and is a testament to the highly focused footprint of the AeroTEM system. The discovery was made without any ground geophysics, with the three initial boreholes, spotted directly from the AeroTEM response, all encountering sulphide, the third hole grading 1.31% Ni, 6.7% Cu and 13.3 g/t TPMs over 42.3 ft.

Canadian Royalties advanced their exploration programs on their Mesamax and Expo-Ungava Deposits using AeroTEM II in 2003 as part of an integrated exploration program. Airborne and ground geophysics of the Expo-Ungava Deposit identified conductive targets that were determined to be high-grade mineralization within a large low-grade system. Drilling into what is now called the Expo Northeast Zone intersected 18.75 m of 2.12% Ni, 1.37% Cu, and 3.41 g/t Pt and Pd. The Mesamax Deposit, a resource of 1,450,000 tonnes grading 2.1% Ni, 2.7% Cu and 5.2 g/t Pt+Pd was expanded and a new resource is currently being calculated. The AeroTEM survey produced such a high resolution image of the conductive mineralization and highly folded formational sediments that Canadian Royalties Chairman Glenn Mullan reported in the Northern Miner 'it is already apparent that the new data being gathered will change the understanding of the geology and distribution of Ni-Cu-PGE mineralization' at Raglan.

The success of AeroTEM in advancing exploration programs has led to the demand for more AeroTEM systems and to the continued improvement of this technology. Aeroquest is committed to continued activity toward the advancement of its proprietary sensor technologies in general, and in taking its AeroTEM technology to the next level of performance in particular.

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